1. Technical Field
The present invention generally relates to lens module, and particularly to spacer used in lens modules and lens module having the same.
2. Discussion of Related Art
With the development of the optical imaging technology, lens modules are widely used in a variety of electronic devices, such as digital cameras and mobile phones. Referring to FIG. 3, a typical lens module 30 includes a barrel 31, two lenses 32 and an annular spacer 33 disposed in the barrel 31. The annular spacer 33 is interposed between the two lenses 32 such that the two lenses 32 are spaced apart from each other. The spacer 33 has a through hole for allowing light to pass through. Each of the lenses 32 includes a central portion 321 for allowing light to pass through and an annular supporting portion 322 for supporting the central portion. Light in the supporting portion can also pass through the through hole of the spacer 32, which may negatively affect imaging quality of the lens module 30.
In addition, to improve an imaging quality of the lens module 30, optical axes of the two lenses 32 and central axis of the barrel 31 must be in a same line. However, during assembling of the lens module 30, misalignment of optical axes of the two lenses 32 may occur due to dimensional tolerance of the two lenses 32 and the barrel 31. To meet trend of miniaturization in electronic devices, size of lens modules are becoming smaller and smaller, and also, it is more and more difficult to align optical axes of different optical components (i.e. optical lenses, spacers and filters) in lens modules.
Therefore, there is a desire to provide a lens module capable of overcoming above disadvantages.